The present invention relates to an exhaust system of an internal combustion engine of armored vehicles for reducing IR detectability.
It is known from German Offenlegungsschrift 39 11 142 for armored vehicles with exhaust gas outlets arranged at the longitudinal sides of the armored vehicle to mix the hot exhaust gas of the internal combustion engine with the waste air of the cooling device in order to reduce the temperature of the exhaust gases.
However, since the temperature of the waste air of the cooling device is already substantially higher than the surrounding atmospheric temperature the mixing of the hot exhaust gases with the waste air of the cooling device always results in an increase of the temperature within the area of the exhaust gas outlets and thus in temperature differentials which allow IR detectability.
This holds also true for the exhaust system of an armored vehicle according to German Offenlegungsschrift 21 30 757 in which a mixing of the hot exhaust gases of the internal combustion engine with the waste air of the cooling device takes place outside of the vehicle at the rear, whereby the hot exhaust gases guided in the transverse direction of the vehicle are mixed with the waste air of the cooling device that exits in the longitudinal direction of the vehicle.
In order to reduce the IR detectability of armored vehicles operated with internal combustion engines, it is desirable to prevent direct visibility from the sides or the top of exhaust gas outlets at the vehicle shell that are hot during operation. This is, for example achieved by guiding the exhaust gases of the internal combustion engine in a downward direction through the bottom of the vehicle shell.
Exhausting exhaust gases of internal combustion engines through openings at the bottom of the vehicle shell of an armored vehicle is already known from German patent 32 21 378. The hot exhaust gases mixed with the warm air to be removed from the enclosed engine compartment is guided into the atmosphere through an exhaust gas channel covering a great portion of the bottom of the vehicle shell and through a plurality of openings provided at the bottom of the vehicle shell and covered with grates.
This known exhaust system has the disadvantage that the exhaust gas channel covering a great portion of the bottom with its corresponding vertical extrusion substantially reduces the size of the passenger compartment when considering substantially equal ground clearance and vehicle height. It is furthermore disadvantageous that the passenger compartment is heated from the bottom by the hot exhaust gases. This requires the application of heat insulating materials at the bottom portion which also further reduces the size of the passenger compartment. Also, the mounting of the long torsion bars of the tread roller springs is impeded by the exhaust channel which extends over the greater portion of the bottom. It is also possible that, when the bottom portion of the vehicle touches the ground surface in sandy or muddy terrain, the exhaust outlets arranged at the bottom are completely or partially plugged, and the power output of the internal combustion engine is reduced by the increasing exhaust gas counter pressure within the exhaust system, or, in extreme situations, may be blocked.
It is therefore an object of the present invention to provide an exhaust system for armored vehicles of the aforementioned kind which only minimally reduces the size of the passenger compartment and which, under extreme driving situations, such as contact of the bottom portion of the vehicle with sandy or muddy terrain, prevents an increase of the exhaust gas counter pressure that would otherwise reduce the power output of the internal combustion engine.